FSE template auto-drafts are not re-created when a theme is deactivated or deleted and activated again.

[carolinan]

I ran into a problem on a website where I had Gutenberg 9.7.0, a full site editing theme and LightSpeed cache installed.

After upgrading to 9.7.0, no issues were found, but I suspect that during the night, LightSpeed cache decided to clean up the database and delete all the auto drafts. 😢 😭 🤦
(It is unclear to me why this was never an issue with 9.6+)

When I logged into the site the following day, the message: No matching template found was showing on the front.
The site editor was not loading any existing templates, nor did it let me create and save any new templates.
When viewing Appearance -> Templates and template-parts, there were no auto-drafts saved.

On to the actual reported problem and help request:
I was not able to find a way to create new auto-drafts.
I deactivated the FSE theme and activated it again, but no new drafts were created.
I deleted the theme and installed and activated it again, but no new new drafts were created.

I had to rename the theme, for it to be have like a new theme, to have the auto-drafts re-created and the theme working again.

-Is there template data with the previous theme name still stored in the database? Where, and how do I clean it?
How do I trigger the creation of auto-drafts if they have been accidently deleted?

[carlomanf]

I'm aware of database cleaner plugins deleting the auto-drafts, but when that happened for me, they just got re-generated again. You shouldn't need to do anything to trigger their creation. This was with an earlier version, so perhaps there was a regression with 9.7. #27910 looks nearly ready to be merged, I wonder if it would solve your problem.

[carolinan]

It happened again without the cache plugin installed. The autodrafts are missing and the front is displaying the No matching template found message